Automatic telephone release.



PATBMBD SBT. 24, 1907.

Y L ALBs. Y u'reggq rammen RELEASE.

innings fuma rm. u, um.

i said teeth are adapted to control and operate a couple will not pass to the other. The shaft 8 has attachedl y although not shown, is mounted en the shaft 8, which shalt rigidly carriis a so-called impulse wheel 9 provided ou its circumference with rio-called vertical im; pulse teeth 10 and one rotary impulse tooth 11. The

of springs 12 and 13, known as the vertical' and rotary impulse springs, respectively'. yLocated between the said impulse springs there is :1 groundipost 14 which, after the switch-hook has been raised and the dial ro tated, is in` electrical connection withthe substation ground G". Byv operating the dial the, subscriber also operates,4 as a result, the impulse wheel 9,"which latter is adapted to engage, through the-medium of. the vertical impulse teeth 10 y Athe vertial impulse sp1-i ng 12, whereby the said spring 12 -iscarried onto the ground post, lwhen the dial is allowed to return, a4 numher of times, -depending upon the numberof teeth 10 that have passed beyond the lug 15 of the said spring 12. After `the'ys'rticial impulse spring is thus operated, whereby ground impulses are delivered tothe verticalline conductor-2, the rotary impulse tooth 11 lways engages the rotary impulse spring'13 once, just before the dial comes to a stop, whereby the said springv 13 is also carried into contact with the ground post 14,' and whereby one ground impulse is delivered to the r0- tary line conductor 3. Rigdly ysecured to th' shaft 8 there is adog-like cam 16 which isprovided Awith a finger, bymesns 'of which the primary circuit springs 17 and 18 are kept closed while the'diul is' in normal position, but .while the dial is rotating-that is, at all times when the-dini is out of normal position-the springs 17 and l18 are kept separated, so that the ground impulses that 1are delivered to-either line itonductor to it any suitable spring, such as a clock spring, whereby the dogcl is maintained id the normal position shown nt A, and whereby when, the dial- Vis rotated the said clock spring iswound up to a certain extent in order to insure the return ot the dial and other parts located on the shaft i to normal position. When thereceiver is on the switch-bool: the latter is maintained in such a position that the insulating "tip shown on the end of the cam-arm 5 holds ground spring 19 sway from 4the ground spring 20, at the same time holding the saidspring in such condition that the insulati ng tip shown on the end of the' iso-called locking cam 21 is retained in front of the itngled terminal of the spring 19, as shown at substation i'#1120, so that when a subscriber `answers, the 'ground springs 19 sind 20 are still retained separated' `by the seid insu lating tip, and ere prevented from coming into cono tuct until after the dial has been rotated, at which time the pin 2?\on the end of the dog 16 raises the locking com 21, so as to drive the inuluting tip tothe position shown at substation A. It will he understood that while the receiver is on the switchhook, and since tho czun 5 is out of engagement with the locking cam 21, the letter is retained in front of thek pin 22 to prevent the shaft 8 from being turned. However, when theY receiver is removed from the switch-hwk the can arm 5 strikes the locking cam 2l, raising the lutter thegrou'nd springs 19 and 2O are in contact. 'thb receiver' is'in a closed circuit with the secondary "to disongagt'r thc inslllaitinu tip on thc 'nd of Ihc locks ing cuni 2l from thc ground spring it). When thc dial is rotuted, however, thc pin 22, by strikingr the roundcd terminal of the lower end of the dog 2l, mises thc lattcr a trifle farther, whereby the ground springs it) and 2U are brought into contact. The object of this construction-that is, in maintaining the ground springs spart until a subscriber has begun to make a cull-is to preventthe occidental grounding of thc line conduotrs 2er 3, orboth, when subscribers are simply 4answering' a call. i,

The substation is further provided with the usual belll 23 which is normally bridged across the line con doctors i-n series with the condenser 24 while the receiver 25 is on the switch-hook, and therefore while the cam 6 maintains the ring circuit springs 2o and 27 in contact. While the said receiver circuit springs are Ain contact, the primary circuit springen and 1S are,

said spring 31 may be pressed onto the contact 32,

which 4latter is fconnected with ground G whenever As shown.

In the primary circuit (the telephone being winding sa, which utter. together with the primary .winding 28, form theninduction-coil at the substation.

The telephone is further provided with the izo-called release springs 34,35 and 36 which are controlled by thc cam-arm 7 and adapted to he pressed into contact by said ami 7. whenever the switch-hook is caused to descend. 4' The length oi time which the said release springs are maintained in contact in order that they maywork effectively may he regulated in :my suitable manner. 1t will be` understood, of course, thatthe switch-hook is also provided with u spring, whereby when the receiver is removed the swil cli-hook is caused to rise to perform the-operations that are assigned to it.

The selector C muy be of the trunk-release typo, and the one herein shown ,is similar to the one described in United States Patent No. 815,321, grunted to Keith, Erickson t Erickson on March 13, |906. As is well known, it comprises the vertical and rotary line relays 37 and' 38, the relay 3j' being provided for czrnsintr the vertical movement of the switch-shaft (not shown) thatarries the line wipers 39 and 40and the privme wiper 41. The rotary line relay 38 is used for operating the privat/e magnet 42, which magnet in turn controls the sri-called side switch that colnprises the sido switch. wipers 4?., 44, 45 and 46. As is well known, theA side switch, in the course of the operation of the selector, is adapted to assume three positions, namely thc normal position known as the first position, the second position at which time theshat is rotittcd, land the third position utV which time the liuc conductors are extended into connection with the linc wipers 39 und 40,1tndwith whatever trunk line conductors the said wipers lnav hnve stormed in engoue- 55 engage tho'iaring .spend to Lize ment. The line relays il? amd 3B are, iurlliermore, adapted, while the Sido ewitcu is in lirez. or second po# sition, to energize the release magnet 47, il they nre energized einmltmieuusly when tlieleirle uwitirflx is in first or second positionA It will be underntood, oi course, that the vertical line relay 37, when n connection is being made, operates to energize the vertical magnet 48, 'which` latter directly operates te raise the switifii-shnt in n longitudinal or vertical direction. .titer tile sind?. has 'been thus raised by the vertifal magnet, the rotary magnet 49, :te soon an tire Bide switch wiper 45 pannes to third, position, operates to romte tile allait. Wipers along the bank le'w el towliicll have been previonely raised by the verti- Ater the eide Hwilch has onlie passed line relays 157 and 3S, aa is well m the line conductors und 3, und tin:- witch 'can only be relased through th medium of tlieeoycalled banlpreleaoe relay l). lfllen once alle milch C has established connection with the switch D, the said relay can only be controlled lyon1 the latterewitch. The seleltor C is, iurthermere, provided with eso-Called normal line (rondini-toro 5l and wllicli term-nnte in the banks nl Conner-tor switches ol ille hundred lo which the substation A belongs. lfit io :mourned that the substationfi is #5220 the said normal conductors will leed Le banks ol the conA nestor Switches oi the second hund! thousendnA--zlial is, rennectors that take Care or" all subscribers. lrelween 200 and i299. Together with the said normal reminders there runs :1. third er private normal uomini-tor Eil Over which lie line #5226 ie made lousy at tlie connector banks while the subscriber abomination .l Calling; and over which The so-rz-.illszi bridge-unveil relay 54 is energized when the line #5 20 is called, in order that tlxe relays 37 and 3S may lie diwunneetefl from each other.

The selecflor l! is identical with the selector C. except that llwre aire no normal line conductora terminating in tlm Side switch wipers 55 and 56, such as the normal line nomini-.mrs el and 52 that terminate in the side switch nini-.radii und 44. Furthermore, there is no bridge-,Cntol'i rnlay er l as tho bridge-cut-ol'f relay 54 0i tile selen tor U. und the line relays 57 and 58 connect directlyV Willi the noir'grounded battery lead 59 instead oi through bridge-cutoff relayeprings, as the line relays 37 and :.f tlie neleelor (l d'0. lfeeeesnrily4 the private normal refilling-.for does not appear in the Selector D. and, furthermore, the shalt Springe, nach as ihe shaft springs 50. 61 and G2 which are controlled oy the normal urso (3 oi the ilililjfrr; mi magnet 4S. to Llurl position the known, nre 'lirsvonneetted iro 2 e phil with. nies-1l, :1:3 well :il En. tile release magneto? and 'linliufi- Another flilleiea-lce in Fillet once ne npparent, nml that is that the prit-:tte mngne (iii has only'two Springs 69 and 7G, which rorref i springs 7l and 7,2 el the eeleotor C; laut the Spring 73 oi the privatenmgnet 42 of tlleseleclor U loes not appear in the awitrh l), which springi is connectA ed w ith the rele-.ilse magnet l?, as shown. .l n the selector l), however, the 'rele-ne magnet in connected with the so-rJ-lled mkqeleeec spring 74 which is controlled by the rotary line relay 58, and wliih spring in adapted to 75 which is cnntrolle by the vertiial.

ille rotary ringnet o5, private magnet the bacioni-lense relay GS.

ed o the liflli time Suid oelertor D which i' ewiieh Contact puint--rnuue ini-:tend el' being connected on earn side oi the milking lino.i

l l l sluit ol the selector Qnre clone away (il course the vertical magnet 64 will be .recogi l the '-onnecior disclosed in United Smtee line relay 5?, whereby when both lino relays 57 and 58 energize simultaneously, the release magnet 57 oi the selector D is. connected with llie third or trunk-release conductor 76, and with the back-release relay t), and through said relay letter is connected with the selector l). lt will be noticeil that in the selector C the side switch contact point, 77, which tlmside switch wiper 45 eng-ngen when the side switch is in third position, is connected directly to ground. ln the selector -D the corresponding side ly the Contact point 734-, directly to ground, is oonnected directly to the third ,er trunk-release conductor A76, and this particular difference in the selector l) is one of the features ol my invention, 4

ln mechanical structure the ronnector E is very much the same as tlie selector, :ind is a mod i lied forni oi Patent No.

815,176, grunted March lil, i906, to Keith, Erickson &

Erickson, the modification being that the connecter E han been adapted to commen battery work, While the connector el said patent is iur local buttery work, ln

the Smid connector E the comlensers and Si) will be recognized at once. wliiuh condenser-s are inserted one hr iront el said uon denoere the vertical and rotary line relays 8l :unl S2 will also be recognized, and in this particular gonnector the v erticnl line relay 8l is connected with the non-ground ed battery lead 59 through a Winding 83 o u ililierental rel-ey S4, while liu: rotin-y line relay 82 is connected troogll e Secund winding ol the said differential relay Se Willa the nenfgronnfled bnllory lead 59. ll. will' be noticed, however. that this communion is made through ilxe springe 86 and 8T of the sii-called infiel;` bridge relay 88, whirl). is a double-wmmll relay, tlie ol whir'h is permanently connected with tlie nongroundecl battery le-.id 59, while. the spring 87 is adapted to be shifted l'rom ille said spring 86 omo A spring Si) which, when the connector side switch passes lo third punition, is connected lo ground. The nennentor side'switch is, as usla-nl, f -unrollei'l by the private magnet'BO. which side switch compries the wipers '91, 32,93 and 94. Said side nwiloli, like die side switches o the Selectors, has, of course, :1. first, seooml and third position. The eid ounneitor ie, iurtiierinore, equipped with the usual vertical magnet 95, the rotary magnet 9G, the release magnet 97, and the ringer relay 98. In the connector, 9.5 is Well known, .bolli Vertical and rotaryningneto 95 and 96 are operated by the vertical line relay 8l, While the rotary line relay 82 controla only the private magnet 90. Beth line relays Sl and 82 are, however, adopted to coniointly Control the release magnet. 97.' .lie differential inlay S4 energizes Whenever tile verri dal or rotary line rel-ny' 8l or 82 is energized galerie; but il ciment. passes through alle windings 83 and S5 nl the differential relay in series, it will not energize, but it will energize when current passes through both of said windings in multiple. The bark-lullige relay 8S, siltliough double-wound. dees not periormin tire connector the functions o n. differential relay. but is adapted to energize when the called subscriber answers, lor the pernos@ of shifting the spring B7 rom main to grounded battery in order to supply the calling Subscriber with talking battery Current. The connector is, furthermoreprovidecl with a couple oi ofi-normal springs 98 apring 86 to'ground at the selector C, when lle 70 i 15 to villl thv Hulisvrihvr :il HitIn-tation #lilith llv und 99 through which the husyrignnling circuit is l vlosvd. which Hpringmlrv controllori hy thv uornutl posit ni'tn ltttl ot' tho vounovtorwitvh H'hnlt. whivh hutvr is not l'hown hul whivh. :tu ix wvll known. vnrrivy thv ifvr- ."5 tival und rohuy lino wipers ltlt und H12 und thv privutv wipvr l'ttt4 'l'hv svlvvtor l" nl' thv vnlltfd linv ifi. it will liu nnllvr- Stond thv snnlv u:- Ilm -vlvvtor nl thv vulling,r nl4 svrihvr. und thv nuhstnlinn #Hilft is thv Httmv nu .Gulistation i\. i i

ln ordvr that thvinvvution muy liv niorv fully nuclvr stood, n dviivription of thv motlv of opvrution will now liv-, sivvn. l

Assuming that thv l-|ihsvri|n-r :it -||hi1|ution wif-lum` rlllllllflt'l hil rvlvi\'v1"=' l'ro'ln Illv Hwitvli-honl; -t und thvu pro vvvdh to opl-mtv thv tliol onvv torvalvh digit ot' thv nurnhvr H20. \\'hvu'thv dizll is opvrutvtl in uvvnrdunvv with thv tirait digit ll thv impulso whvvl il, through thv mvdiuni of its vvrtivul und num-y impulsv Lvvth, opvrutvn toground linut thv \vrtivul liuvvonduvtorBouvv und thv rotury linv vonrlnvtor Il onvv. Whvn thv li-.nl is opvrutvd for thv rvr-vond digit. l thv linv vouduvtor:v 2 und il :irv zigniu grouiidvtl onvv und onvv, rvspvvtivvly. ["or thv thir d digit 2 thv vonduvtor 2 is grouutlvd twitrv :nul

thv vunduvtor I, onvv, und for thv lust digit t) thv vondttvto 2 iN groundvd tvll timvs and thv vonduvtor Il rinvii'. 'lhv iiupulsv vorn-quindint,r to th:l first digit l znv, of voursv. dirt-vtvd to thv svlvvtor lhv impulsv to thv vvrtival linv vonduvtor 2 vnunvs thv vvrtivol linv rvhiy `3'7' to hv vnvrgiuvd liy u flow o1' currvnt front tho Huh-tation ground t through thv ground springs lttnnd 20 to thv ground post I4. thviivv to thv vvrtir'al impuluv sprint,y I IZ, vvrtivol linv conductor 2. sichswitvh wipvr 11%, Iirrit-pouitiou vontuvt point HH to thv linv rvlay It?, thvnvv through mid rvluy und through thv hridgv-cutol'l rvluy springs |05 and lttli to tht- Imttvry lvnd 5U, und i throughhnttvryltogroundf. Thvlinvrvluy I17prv esvu tht,l linv rvlny springt' ttt? und 10H into vnntuvt, whvrvhy 40 n flow ot' vurrvnt is sont through thv \vxtiv:il mnonvt `ttt from ground (11', through thv Iuid spi-it w ttlh' und IUT. privzitv nmgnvt springs Tl I.ind T2, vvr vul umgnvt 4h to thv lutttvry lvzul Titi, :ind through huttvry It to ground (i. In u uttlunor wvll uudvrstood. thv switch slntt't. is ruiiivd onv stvp, whvrvhy thv Hlmtl wipvrs litt, Attl und 4t urv rniiml to thv tirnt lmnklvvvl opprwitv thv tirxt trunk linv thvrvof. 'Ihv Hch-vlnr ll livingr thun opvrntvtl, thv

impulso to thv rotary lino vomluvtor It ummm thv rotzu'y linv rvlay 3H to vnvrgi/.v hy u tlow of vurrvutA [rom 5() groundt to thv ground post l-t, :tud through thoromry impulso Hpring lt'to thv rotary linv vonduvtor h', th'vnvv through thv Hidv nwitvh wiper 44, vontnvt point 109 to thv rotury linv rvlny 18, thvnvv throiigh Huid rvlay :nul through t'hv hrdgv-tutfm rvluy Nprings llt), 1,05 hnd Ittti tn thv lmttvry lvud 59, and through buttery it to grou-rid (t, 'lhv mid linv rvlnytloporutcs to close oonnvvtion hvtwovn thc springs tllnd 108, wlgl'crvhy u tlowotf vurrvnt rvsvnt through the privato muguet 42 from grou ud Gthmugh Huid lepri ngslttlt andi 11 ,through :mid priv-utc magnet, .42 to tho buttery lead 59, und through buttery Il to ground G. `Pho prihut'magnet living thuis opomtvd pvruiitu thv sidv Witch to trip to nocond position, :it `which timo thv sido switch wiper 46 ongagos the groundorl coiitvt point. 112,l whereby n 615` circuit is established through the rotary magnet 49 from ground il, through said :otztry nmgnvl to thv huttvry lvad 5ft, und thrtunh liilttvry ll to ground (i4 'lhv rotin-y unioni-t thvu lit-gint` to rolutv thv shalt, uhivh lzttlvr thvn vurrivs thv privutv wipvr -1l nuto thv |i|2 t montan-t of thv lil'nl lnvvl ni thv privutv hunk. li thll trunk linv lvm|in;;'l`ron1 thv Inst. Imnlc tvrininnl ol' thv tirol. lnlult lvvvl in busy, thv privutv wipvr l1l will tunl thv privutv vontrivt `groundvd, uincv thvrv is n svlvvtor Hiiuihir to thv .s'vlvvtor ll in vonnvvtiou with thv tirHt. trunk linv nl thv tirnt lvvvl, the privntv Sidv Hwitvh wipvrnl whit-h svlvvtnr, similar to lhoiliv iu'ilvh wipvr 15. is in third position und in vngtnrvlnvnt with :t groundvd voutuvt point similar tn thtl vontnvt point 77` l".\idvutly, thvn, thv guurding potvntiol is vstohlishvd.

att thv pri\':\tv honk voutuvt, through thv dvxvrihvd ovvupying .-vlvvtor, hy way ot' thv huvk-l'vlvusc rohly oi V-uid svlvt'tor. uiinilur to thv liznlvl'vlvosv rvhly 5U. 'l`livt't-l`orv, :is soon :in tho prirtltv'wipvr l] vngvgzvu thv mid groundvrl vontnvt, un vnvrgizint; vircnit is vfituhlishvd through thv privato ningnvt. 42 that :tguin vnvr ri/.vs runid privutv inngnvt und lot'ks the Hielo switch in svt-ond position in ordvr to hohl tho ivnvrgfizirn;v circuit [or thv rot-.try nuiguvt -ttt until alti-r tho shalt wipt-rs huvv hvvn vurrivd hvyond thv lust husy trunk line and into vngngvnivnt with somt.- idlv trunk line. This vncrgizing vii'vuit t'or thv p utv inzlgnvt vx'tvnds from thv groundvd privo-tv hunk tontztct through tho privatov wipt-r 1t, :ind through thv hack-rvlvusc rvlay 50 to thu f nidv vuitvh wipvr -t` thvnvv (since said sidv switch wipt-r is iu Avr-ond posit ion) through tln.I private magneet, 42 to thv lmttvry lvnd 5t, und through battery li t0 ground G. As soon us thv privato wipvr 4l has livon advanvvd hy thv rotary magno! 49 hvyond the last husy or groundvd privato hunk vont-uvt, thv vircut through. thv privato maigrir-1,42 is again larokernat which time thc aidv switch of thv svlvctor is pvrtnittod to paris to third position, ut which instuut thv vnvrgizing circuit; is hrokvn through thv rotury :ungut-t 49, und thc line conrluvtori-i 2 und it rnro oxtvndvd to thv linv Wipvm 39 and 401m soon as thv sido switch wipt-rs 43 :md t4 vngngv the vonmvt points 113 and 11-1. Thv linv wipt-rs 39 and 40 having prvviously vngagvd thv trunk conductors 115 und l tti, thv subscriber is, thvrviorv, directly vonnvctvd with tho svvondmolvctor D. to which Hvlvctor the in1- puhivs.vorrvsponding to thv svt-0nd digit. uro dirvctvd [or opvrrtting Huid svlcttor, in tho sumo mtmnvr that thv svlvvtor (Y wus opvmtvd. It, will also he undvrstood that un soon as thv nidv switvh wiper 45 passes to third posit ion, into contact with tho groundvd Contact point 77. u guarding potvntiul is established at the privato wipvr 4 l. by way of thc hack-rclcase relay 50 for protvvting thv avizod line from interference, which guarding potvntiul is, of course, communicated to the privato bank contact engaged bythe private Wiper 41, and tht-nce to nll other privato bank contacts connected in multipla therewith. 1t is assumed, ol course, that. the said trunk conductors 115 and 116, and lso-Lhe third or trunk-relance conductor 76, are thv conducwrs of tho tirst idle trunk line which the selector (l has soin-1l.

The ground impulso to thc vertical linv conductor 2 for thv second digit; 1 energizvs thv voi-tival linv rvlny 57 hyo flow of current from ground G to thv linv vonductor 2, to tho sido switch wipvr 43, to thv linv wipt-r .'19, nido switch wiper 55, vo'tact point 117, through uuid lint/I roluy 57 to thu hattvry loud 59, and through but tory B to ground G. The line relay 5i', thereoreoperetes the vertical magnet 64, whereby the line Wipers 11B and 119 and the private wiper l2() are brought opporitc the first contacts oi the first levels of their rcspcw tive banks. when the` rotary impulse coince over the rotary line conductor il the rotary line rei-oy 58 is in turn energized by a. flow of current from ground G to the cond nctor 3, eide switch wiper 411, line wiper il), side switch wiper 56, Contact point 121 to the rotary linoreloy 58, und through said relay to battery lead 59, thence through Vbattery Bto ground G. The said rotary line relay 68, of course, operates the private magnet 66, which in turn operates the sido switch from first to second position. When the side switch `is thus tripped to second position, the circuit is closed through the rotary magnet 65, when the side switch wiper 122 engages the second-position grounded Contact, whereby the shaft is rotated until an idle trunk line is found. It is to be noticed that if the first trunk line is busy, as was assumed in connection with the selector C, the first Contact of the first level oi the private bank will 'l be connected to ground, there being'7 of course, sonneY other selector similar to the selector D on the trunk line which is protected by the said first private bank con` tact. The connection `to ground from the said bank contact will be the same :ts-that established by the rse-v release conductor 76, back-release relay 50 oi theseleo tor side switch wiper 45, Contact point 77 to groundv G. lt will be noticed, therefore, that the guarding potential forifirsoselector trunks as well as for second#i selector trunks is provided from the firstselector ground terminal 6*; t'he guarding potential for the firstjselector private wiper 4l being established through vthe back- ,i release relay'o, und for the private wiper 129 through the backreiease relays truand 68." Therefore, when the' selector private Wiper 1Z0-is rotated onto the first con-u tact ofv the first level of the privlte bank (which-contact it is assumed is grounded, as expiairied), an energizing circuit is restablished through the privato magnet 66 which maintains `the side switch'oi the selector D in second position until-the wipers are Vcarried onto an' idle trunk line, at which time the energizing circuitfor the private magnet 66 breakeand the fatter side switchv to poney to third position.

permisos.

the `contactpoints 124 and 125, the trunk conductors 115` vand 116 are in turn placed in connection with the line wipers 118and 1,19 and, thereiore, with the trunk conductors 126 andV 127 in'engagement with which said wipers have stopped. Furthermore, 'when theside switch wiper 123 engages the contact point 7S, Ythe trunk-release conductor-.761s put in connection. with the private wiper 12B-through the hack-releaserelay 68, thereby ,placing the Vseid privati; wiper 12Djn con-- nection with-ground Gi at the.' iselectorC; and this con noction establishes a guarding potential at the said private wiper 120, which is communicated to tlie'engoged private bank contact and to all other private rhonk contacts in multiple therewith, whereby the trunk line the conductors 126fand 127 of which have the connector E and also the differential relay S, the

latter to no consequence for the time lacing` `The circuit extends from the substation ground G io the condoctor 2, to the trunk conductor 115 and to the trunk conductor 126, thence through the Iline relay 81, and through the winding 83 oi the differential relay 84 to the battery iead 59, thence through battery B yto ground G. Said relay by pressing the springs' 129 and 130 into Contact energizes the vertical magnet 95. by a flow oi current from ground G5 through the said springs 130 and 129, and through the springs 1.31 and 132 to the side switch wiper 94, contact point 133 to the vertical magnet 95, thence to the battery lead 59, and through battery B to ground G. The connector switch shalt is, therefore, raised one stepA each time that the line conductor 2 is grounded (twice in all), corresponding to the digit 2, whereby the wipers 191, 102 ond 103 are raised 'opposite the rst Contact of the second level oi their banks. The ground impulse delivered to the rotary line conductor 3, of course, energizee the rotary line relay 82, and incidentally the dierentialrelay- 84, by a iiow of current from ground G to the line condoctor 3, .trunk conductor 116,'trunl conductor 127 to the line relay 82, thence through the windingl 85 o thel differential relay 84, and through the springs 87 and 86 of the bock-bridge relay 88 to the battery lead 59,

thencethrough hattet-y B to ground G. Said relay 82,

therefore, tripped to second position, and the side switch wiper 94 shifted onto the contact point 135,

kvwherein; the following impulses in :nevel-tical une condu'ctor 2, corresponding to the lastdigit 0, will, through the vertical line relay' 81, effect to operate the rotar;Y

magnet 96. The tenmpulses to the said conductor 2,'

.of course, operate the line relay 81 ten times, which in turn operates the rotary magnet 96 ten times by sendngva flow of current-:each timerfrom ground G to the side swtchwiper 94, Vcont-,act point 135, throughthe rotary 'xna'g'net`96 to the battery lead 59, and through battery B to ground G. The shaft is, of course, rotated Yten steps, whereby the wipers 101 and 102 aroplaced -in consctwith the normal conductors 136 and 137, and

Y the priest@ wiperl in contact with the pryate nori conductor 138. The last impulse to the .rotary line conductor 3,V of course, operates the rotary line relay 82 Y a second time, which latter in turn operates the private nignet v90 and trips the connector side switch to third position, thereby extending the trunk conductors 126 end 127 into electrical connection with the normal condoctora 136 and 137 through the condenser-s 79 and `80.

'line conductor 2, lhemerticnl line relay lil is, of

course, itgatin energized, and the differential rplzty SI1-ie also energized, :is nlri-:idy explained. Said relays 8| 'f und 84 then opi-nite :it the saine time, the relay 8l to closithe line relay springs |29 und 130,arii1. Linl differcntiul rchiyl to elm-ie thtx springe |38" and |39, Wherehy, since the eide switch wipt-i294 is in third 'position and in engagement with thc contact point |40, an cnergizing circuit is established for the ringer relay-98 from ground through the springs 130 and |29 to the side i-iwitch wiper 94, through the contact-point 140, 4ringer rol-.1y 98, `ztiidthrungh thc springs |39 land 4131%" to the butti-ry lend 59, thencethrough battery ll to ground Gf Suid-reliyfli,4 then fpm-tites to carry, ille springs 141 Iand 142 into' engagement with the springs 143 and 144, whereby the ringer generator 4,ll is bridged across the line conductors |45 rind |4l of the culled substationior signaling the subscriber. il' satid subscriber does not answer, the subscriber' :1t suiist-.ition 'A hangs up. his receiver und causes tlic'relense-springs 34, 35 and 3bv to he pressed, into contact, whcrchy the line conductors 2 :md 3 are grounded simultaneously from the snbstation ground Gte thil rclensc'spring 36, and through the springs and 34 to the sztid conductors 3 and 2. As a result thil line rel-,lys 8| and 82 of the connector E are energized'siniultnliixiusly, und the differential relay 84 is iilsn energized'. lista result the trunk-'release springs 147 and 148 of the connector are pressed into contact, whereby the release magnet 97, in euries withthv back-rc|casc-relny (S8 of the selector l), 'and in series with the back-release relay 50 of the l selector C, is energized, said back-*release relays [i8` and @energizing also. As soon es ,the release magnet '97 cnergizes, the connector side switch ,and'switch shaft :tre restored, Ifind the energizing circuit for the bridge-cut-oil'relay 149 is broken, said circuit being Vestablished as soon as' the (ounce-tor establishes con nection with the selector F. kThe said energizing circuit isyoiceursc, established ronfgroiind G" through uw sine-witch wipres (which is new' in anni` pesitien) to the prit/ aw wiper 103, ,private normal 13B, switch shaft spring, 150, contact point 151 to the bridgecut-ol relay 1,49, and through said relay to the battery lead 59, thence'tliroiigh battery ll to ground When seid relay `149 energi'nes, the vertical'and rotary line relays 152- and 153 of the selector F are disconnected from each other und frein the battery l'ead'59. Atth'e rtime tiine that'therrelcase magnet '97 of the connector NtQis -the connector i-iwitoh 'shaft and side switch,

ag tatedj'theliack-relcase relay 68V oi the selector D presses th'e releaiesprings 154' and A155 into Contact,

whereby an energizing circuit isestablished through therelcase magnet 67 of the select-or D from ground G7 `,throughlhe aid springs 154 and 155, `and through th release 'rn'agnet 67|l to the .battery lead 59, thence through `battery to ground Said release magnet,- upon energizing, `attraete its armature andy sets the re leasing apparatus in readiness to restore the switch D` na soon as the ground connections to the line conduc; tors 2 and 3 nrc broken. Similarly, the haelt-release relay 5l), upon energizing, presses the springs '154) und 157 into cuiller-t, -whereby the release magnet 47 of the selector (j ie encrgizcd by a llow of current from ground G through said springs 15G and 157, and through the release nnignet 47 te' the battery lead 59, thence through battery B to'ground'G. The relents(A relay 50, of course, upon energizing, pute the releasing apparente in readiness to restore the switch Cfas hais been describedA in conncttionwith the switch D. As Hoon as the ground connectionlto theline conductors 2 and 3 is broken, thcfline relays 81 an'd 82 and the differential relay 84 at thev connector E 'denergize, whereby the trunk-release circuit that comprises the release magnet 97 of the connector, the back-release relay 68 of the selector D, and the backreleaserelay 50of the selectorll is broken. 1n this way the connector switch E is fully restored. The release magnet 67 oi the selector 1 D fully restores said switch D,Vand the release magnet 47 'oi the switch (l likewise upon denergizing fully reswressaid switch' C However, if the callel subscriber does answer, as soon as he'removeeihis receiver 158', the switchhookv rises and the primary circuit springe 159 and 160 close in contact, whereby a circuit yiseetaldished'for energizing the back-bridge doublewound relay BS of the connector Said energizing circuit: may' be traced from the side lswitch ground Gf' at said connector to the side switch wiper 93, through thewinding 1'61 of the back-bridge relay 88, through the line Wiper 102, normal conductor 137, line conductor 1:16, uprimary winding 163, transmitter 164', primary circuit sgi-ings 159 and lfyverticalline conductor 145, vertical normal conductor 136,1line wiper 101, side switch wiper 91, winding '165. of the back-bridge relay 88, `through the differential relay springs 166 and 1738 to the battery lead 59,iand through battery` B to ground G` The said relay 88,1ipon energizing, and as previously explained,I shiftethe'lprng R7 from the nonlgrounded battery spring `86 onto the spring 89, which spring, sin'ee'the side switch wiper 93 is in third position, is connected to ound G'z.A Therefore, the calling subscriber is providedvwith talking battery current which flows from ground Gdthrough the said springs 89 and87, winding 85 of the differential relay 84, rotary linerelay 82, notary trunk 4conductor 127, trunk conductor 116, rotary lineconducwr 3, through the `primary winding 28 at the substation hand transmitter 29 be k to the vertical line conductor 2, thence to theltlunlc conductor 115 and` tothe trunk conductor 126, passing thence to the vertical line relay 8l and winding 8311i the-differential elay 84 to the battery the line relays' B1 and 82 of the connectorenergize, but the release ofthe switches is prevented, since the dil erental relay 84 doeii notvenergize. After the subslcribers are throughltalkng thecalling subscriber may line conductors 2 andv 3 are grounded, as already exlbeing' lconnected to main battery through the winding j 89 of 'the differential rlay-84, remainlfs energized aitei 1Tauch grounding;l but the grounding of the rotary line conduct/or 3 fixstoperates to effect a short-circuiting of the rotary line relay 82, whereby said relay is dener'gized'-, and a. shqnrfcircuiting of the winding 85 of l ringe'r relay springs 162and '142, side switch, Wiper 92,

lead 59, and through battery B lo ground G. Of course,

release by hangingupjhie receiver, at which time the 4plained. The ,vertical line relay 81 of vthe connector, l

the differential relay S4, where-,hy the saiddilfernntiul A relay is energizod by tliecurrent in the winding 83. As u result tho differential rr-lay springs li and 138* are separate-d, and therefore tho douillI--wound molo 5 bridgxl rainy 3S dvnorgixos, -which lutter thon nlwrutvs to restore the springs S6 and 87 into contini, thus rustoring llorotnry lins relay S2 und the` winding 55 of thv differential relay 84 to noi-nml rumor-tion with thebattery lead 59. As at roouliy tho rotny lino roluy Bil in renorgizod. und the winging B5 of tho difforr-nti-il relay 84 carries current iu suoli direction as tu assist the winding 83 in its operation. As a rvsult the vertical and rotary line relays 8l and 82 and tht,l difierontisl relay 83 are energized simultaneously. The result of this vcondition is that tho swithes are all rsleasd, as descrihod, at the instant that theA ground is removed from the lino conductors 2 sind 3.

It will he understood that the calling lin( s :is well as Called lines are protected ity-guarding potentials The calling lino #5220, for example, is protected at the instant that the switch shaft, upon rising, permits tlv: Y

off-normal spring 6l to engage the c'ontmt point H2, af, which time the privato normal conductor 53 is placod in connection with ground G9 in order to prevent any Calling subscriber from molesting the substation A alter the selector C has operated as doscrihod. On the other hand, s called lino is protcted by a guarding potential established hy the connector that cslls. For vxninplo. the lino #112() is protected. by a, guarding 'potontsl which is ostablishr-d by the privato Wlpvr l0?) Wlwn the side switch Wiper 93 engages the side siifilvh Contact point that is connorfted wit-h ground G6. This guarding potential isY of course, Communicated to the niwi'ttto bank Contart, which is engaged by the :nid privato wiper 103, which guarding potential is. ,lurlhmmoro7 used for energizing the bridge-cutoff relay 1-19 o the selector o the called lino, as alrcrady explained. This guarding potential is also con] niunicatod to ull Contact points in multiple with the Contact that is engigf-d by the private wiper 163. Ii thsconnector E attempts to connect with a busy line the priwite wiper )Oil will meot a grounded Contact point While thu sido switch wiper 93 is in second position, and vifhilo thi privati,- magnelis energized, and, tlwroore. While tho springs 167 and 16S are in Contact. A ruimere Giri-uit is lliure fore established through the rvlvsse ning-nui Si? ,from the sail grounded privato bank Contact which mslm-vs the connector switch The calling .subscriber will then, upon findingput that the line is busy, ground the line conductors 2 and 3 :is before, which will operato to relense 'the switches, as in the case desvribed wiwi-v ihr called subscriber did not answer, It will lw nudi-rstood, of roursv, that this rolt-:iso occurs at the instant that tlu.- subscrihr-r sends in the lastiinpnlsrlo thi rotury line condurtor 3. 4

From thv foregoing it will he seen that l zulrnnin geonsl'y connect thvl rolo-iso relays of all the scler'tors. or nutomntic switrhcs, directly in series with tho rf-lvnsif magnet of tho conm-rotor. in one long trunk-ruinoso rirr'uit vxtvndng through all .of theswitvlivs and including thv liattery. The release rvlays o the selectors vs ('11 lim-'o it local release circuit to rontrol, but by onvrgixing :ill of tho release relays simultaneously, tlw ri-lr'nso tlurnliy vlvcted between calling and called tiflvlshono 65 lines is pinrtically instantaneous, its ono soloetor, or :un

tonuitic switch, does not wait for the other in roloasing. It is obvious that the resistsinrv o th(l various roluys and magnets can be changed or varied in iwcordanr-rwi th diffvront requiromr-nts. 'lho buttery is prvilfinldy o titty volts. and with tlm system as shown l find tf1-L good results are obtuinod wlivn the relay L nd :originals are g r in the following rosistancos: Thor fresse insigni-t il? or' tho sonneotor sixty ohms; tho release magnet i? oi the solc'otor C and the release magnet 67 of the selector D six ty ohms each; the hack release relay 5i) oi tho solei-tor and the baek-release relay 68 o the selector l) onwhsli ohm @zichA It willl lm understood, of

ist all of the rlsys, switches und othor circuitelosmg devices, or impulsetransmitting devices, uro suitably sjustsd to Close the different ircuits or thv proper length of time, or to sund the required olortricsl impulses, so as to obtain the desired results and thu de scribed mode of operation.

From the description that hss pre-ceded it will 1w evident. that tho calling subscriberlnnxy ift-leurre iluA switchus even before he has completed a cuil. H0 muy ,release the switches at an y time, for examplu, while tht` side switch o th'o soliector C is in third position and hoforo the side switch o the selector D has passed to third position. In that case, when tho line conductors 2 and 3 are grounded simultaneously, thv line relays 57 und 25S of the selector D energize simultaneously, carrying tl'wl springs 74 and 75 into contatti, and thus establishing n release Circuit comprising the roll-sise magnet G7 ol the selector D and the brick-release relay 50 ol the. serlortor C. The current in this reid-isf, circuit will ilo-nf Irmu ground *l* at the solcetor C through the bachi-@losse n lai-y 5U. trunk-release conductor 76, tliroughrilio springs T5 und Tl tu the roleasomagnet G7, tliculo to the linttory lr--lnl 59, and through battery B to ground G. 0i' coursv. tho release magnet. will :it once enorgize, and also thv bunk-release relay 5U, which will in turn raus-o th(A reluiise magnet 47 to snergizv. Both rolensv inagnets Yj? und 6? will remain in readiness to ridosso the switohes as soosA its thi, ground is removed from tho linf- Condua'tors 2 and 3. :is is Woll undorstood. At 11u-it instunt ilu ioluys 57 and 5S will duomo-gis@A destroying thv omrgizing vircuits for the ningunl? und the relvtisv relay 5U, whirh lutto: (namely the relvaso relay v50), upon firfiwrxgiiing. in turn lmnks the energizing Giri-uit of die rolmso ungut-t 4:1'. thus ifi-inging about the rslcasn. l

hol I clnizii'as my invention isz- 1. ln a tolephone exchange sysirln, the combination of n calling eepionv lima willi-tl Idool-mue lino, u counselor for completing connection with also millor! line. trunk tinoY und n plurality ni' trunlring swilirln's for nxnudiug4 connection from Hiv milling: llno to the said conluvml'. n irl'nulnli-ll runlvrulmme circuit suitnbly controlled n! thv connector nud cxuuding through and lnrluilin; ull of the sold uutoniutic switches in series, and a 'mttury im umg-izmir said relu-.isc circuit.

in :i ion-phono exchange system. i1 plurallty'of sw- !ermi's und n vormen-tor, nach selector providodlwith n avions-t ulny, said connecter p'rovlded with a release miur nvr, und n trnnkd'ulezlse circuit including snm magnet und avlium in serios with each other. together with n simi-eo' or mrs-em for f-rwrgzing said :mism-t und rrlnys.

In n tulrplimn rxclmngv systrm, the combination o!" u Ihsl-svlvcwin :i svvomtsvh-crnr. mimmlol. u trunkVv release itin-uit vxvndng from :hv unie-lor to the said suivi-tors'. n talking Circuit excluding said ri-lvnsc circuit. ulvrironmgnl-ls for said conmwtor und solvutols, Mid

clcctromngnvtn included ln vries in unid ruin-usw circuit, l'elmwe mechanism rnntruilud by Huid elwtronuurnetn, und u Huurcc uf currcut for illciuniun in sutil rvieurw cirrul In i-nri-gizisaid civctruuuugu-lr;

44 lu n telephone rxciumgv syslvin, tlui-uxnliinutiun nt' u culling tvlcpimne iinu.u'ralitd lult-plunuliuc, nu nutjin muti(- t-onuuctor fu cumpli-ting tim .-unlil-utinu lilrl-clly with liuculld liuc, trunk linv und u plurality nl' trunking Hwitcliwi for vxlt-nding cunnvctinn from liul culling illuA tu tbc said cnnnrctnr, :n vitl'h uuclifmixni by which lluclllug: suimcribrr contrnls tlu npvrtliiuus ui' Huid runnl-vtm' und trunkiui; Hwlttflum, um nl :mitil trunkini..r switches balm: liuiivltiuul in llic calling tr-ivplmnu limi` u Hunk-release cin-uil mirtilli-li at ilux cumu-clor und ix tcnding through ull cf snit! trunkiug switcliw, unil 1t Nuurcc uf currcnl for cucrgizim; uuid rcluus'c circuit.

fi. in u lrlvpliunv vxuimngv sysitin, flic ronxlilimtinu ui mi uutonmtlll switch. :i ivlvplmuu llnv, liu-nim including n plurality uf twin-)lus for cxtrmiiug,conm-climi frmn tinsuid tt'icpliunc liuc tu tiltsud automatic switch. u trunkl'vleano r'icult muti-climi ut tlii` :iutmuutic switch und ix|- cludtnf!l thc said swllclics in Hvrius with cnuii ntlirr, und u murcc'ui' current fm' energizingv sziiti 'circuit tu tvlrztht tiu` automatic switrii null switches, i

ti. in u tulcpiiunc exchange systl-m, thu cuniliiuuttuu bf` invulling tvicpiiouc line, n culled tuicplionc liur. n. cqnncctur. fui' cumple-ting coruwction with the cailud linc,. iluuk ilhvs and a plurality of t-runking tswltciius fcr cxt|-ndiug annum-tion fl'nm tht millingl Iinv tu tliesuid ronnm-mr, u ii-nulidad t:r|inkrcica.-:` circuit uitaiiiy conand c'xtcndlng tiiruugli and inv vinding .ull of thvy unid automatic. switcliws in Hcrics, u hum-ry for cncrgizing said release circuit, und sulihcrllicrs lull-nimml transmitters receiving lulkim.,r rurrvut from suid lmtlel'y. i f

T. in ateicphone excliungrf syslvima plurality u! sclmfturs nud u connvctr, en'ch seicctnr iroviliwi .with u vult-imc relay, unid connector pruvidcd with u rllciuic'mmnot, u trunk-rcitgyue circuit including said muguet und rulnys ln sutiles with each other, together with a -suurcc of current for energizing said mugnetand relays, ulid n sub- Nvrilu-r's mlephone from mid source.

transmitter receiving milling currvntA liti shown um] llt-scribed.

Sigurd hy mc nt Chicago. tuuk cqunty, Illinois, 'this 1st duy of February, 1907.

F. iI. Darin', JENNm Nimmt. 

